Study On Structural Strength Of Catamaran

Catamaran is a particular ship type. Because of its excellence: broad deck, stable navigation, flexible manipulation and so on, catamaran is becoming more and more popular. However the structure analysis of catamaran is more complex than the mono-hull ship because of the complicated structure and exterior loads of catamaran itself. There are several instances prescribed by Chapter 15-catamaran structure supplement prescript in CCS "Freshwater Ship Classification and Construction Criterion" which need to be calculated directly. But presently we have no concrete prescript in the field.With the great development in modern mechanics, computational mathematics and computer technology in hardware and software, finite element analysis has made rapid progress in both theory and computational technology. More and more general -purpose or specialized programs have been put into use, and costs on performing FEM are reduced sharply. The structural direct calculation method has been one effective method in analyzing ship strength wholly and precisely. Reasonable finite element model for ship structure strength can evaluate the more exact stress state. The thesis made some primary attempts in these fields.Firstly thesis began with the actual state of catamaran research, introduced its structure character, performance, loads calculation. After presenting the former experience formula, this thesis deduced a series of concise formulas. According these formulas, exterior loads are calculated. Then the thesis made use of software ANSYS to calculate the strength of a catamaran of 66m length, selected reasonable restraint form. In the whole ship computing result, the cross-structure stress is the most important consideration. According the regularities of distribution of the cross-structure stress, the thesis gave a simplified finite element modal. In this thesis the finite element model of two engineering catamarans are calculated under multi-load cases. The distribution of stress and deformation are given. The local stresses and stress concentration on the connection area of hull body are analyzed intensively. Because the wave-loading calculation is the puzzle in the directcalculation of catamaran, a calculating wave-loading computer program is developed in the last part of the thesis. The specific navigation area, loading, ship type and so on are considered in the program, so it can calculate the exterior wave-loading more exactly. All of these, including the argumentation of formula, the ship model building, loads and restraint, and so on made references to the correlative criterions.